package com.hrb.douban.mview;

import android.content.Context;
import android.text.Spannable;
import android.text.SpannableString;
import android.text.style.ScaleXSpan;
import android.util.AttributeSet;
//设置字间距
public class ChangeTextViewSpace extends android.support.v7.widget.AppCompatTextView {
        private float spacing = Spacing.NORMAL;
        private CharSequence originalText = "";
        public ChangeTextViewSpace(Context context) {
            super(context);
        }

        public ChangeTextViewSpace(Context context, AttributeSet attrs) {
            super(context, attrs);
        }

        public ChangeTextViewSpace(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);
        }

        /**
         * 获取字间距
         */
        public float getSpacing() {
            return this.spacing;
        }

        /**
         * 设置间距
         */
        public void setSpacing(float spacing) {
            this.spacing = spacing;
            applySpacing();
        }

        @Override
        public void setText(CharSequence text, BufferType type) {
            originalText = text;
            applySpacing();
        }

        @Override
        public CharSequence getText() {
            return originalText;
        }

        /**
         * 扩大文字空间
         */
        private void applySpacing() {
            if (this == null || this.originalText == null) return;
            StringBuilder builder = new StringBuilder();
            for (int i = 0; i < originalText.length(); i++) {
                builder.append(originalText.charAt(i));
                if (i + 1 < originalText.length()) {
                    //如果前后都是英文，则不添加空格，防止英文空格太大
                    if (isEnglish(originalText.charAt(i) + "") && isEnglish(originalText.charAt(i + 1) + "")) {
                    } else {
                        // \u00A0 不间断空格 碰见文字追加空格
                        builder.append("\u00A0");
                    }
                }
            }
            // 通过SpannableString类，去设置空格
            SpannableString finalText = new SpannableString(builder.toString());
            // 如果当前TextView内容长度大于1，则进行空格添加
            if (builder.toString().length() > 1) {
                for (int i = 1; i < builder.toString().length(); i += 2) {
                    // ScaleXSpan 基于x轴缩放  按照x轴等比例进行缩放 通过字间距+1除以10进行等比缩放
                    finalText.setSpan(new ScaleXSpan((spacing + 1) / 10), i, i + 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
                }
            }
            super.setText(finalText, BufferType.SPANNABLE);
        }

        public class Spacing {
            public final static float NORMAL = 0;
        }
        /**
         *  判断是否是英语
         */
        public static boolean isEnglish(String charaString) {
            return charaString.matches("^[a-zA-Z]*");
        }

    }